A number of devices of the general type described above, including a spirally or helically wound flattened tube of semi-permeable membrane are known. While each of these patents teaches the use of such tubular semi-permeable membranes helically wound around a core and including various types of spacer material separating the individual turns of the tubular membrane themselves, one of the elements of each of these devices is means for delivering the fluid to be treated, such as blood, to the inside of the tubular membrane and for removing the thus treated fluid therefrom. In U.S. Pat. No. Re 27,510 such a device is taught which includes the ends of the tubular membrane being folded around a highly elastic terminal tube 9 and pulled together under strong friction so as to be leak-proof. The patentee thus employs a conical bore 8 of a confining rim 10 as best shown in FIG. 4 thereof in the outer casing 13. Similarly, in U.S. Pat. No. 3,709,367 another such device is taught which in this case includes connector units 18 and 22 for connecting the tubular membrane to tubes 20 and 24. Similar teachings are contained in U.S. Pat. Nos. 3,712,474 and 3,743,098.
Yet another such device is disclosed in U.S. Pat. No. 3,880,760, which in this case includes a core cover section 2 adapted to mate with a core base section 1 with the ends of the tubular membranes therebetween. A similar structure is employed at the other end of the tubular membrane, as shown in FIG. 2 thereof. In a similar vein is U.S. Pat. No. 3,962,095 which discloses blood inlet and outlet means 26 for connection with arterial and venous lines attached to the casing using wedge section cover plates 28 which are screwed to the casing and which form a seat for the blood inlets and outlets. Finally, U.S. Pat. No. 3,963,621 discloses yet another such membrane device, in this case merely stating that tube 18 communicates conventionally with the end 20 of the membrane 16.
In a similar type of device shown in British Pat. No. 1,417,446 the patentee again merely discloses that the core 1 includes an opening in which a sleeve 31 fits in order that the blood tube 12 can be connected to the membrane tube 2. Another substantially similar device is shown in British Pat. No. 1,433,512. Finally, German Pat. No. 2,514,580 shows yet another means for connecting a tube to the tubular membrane.
While some of these known constructions operate in a relatively satisfactory manner, each is still subject to certain disadvantages. Among other things, these constructions now on the market contain a large number of parts rendering assembly more difficult and producing a number of sealing problems. It is therefore an object of the present invention to provide a simple construction for the aforementioned type of diffusion device which includes a smaller number of parts which can be easily assembled and to therefore eliminate a number of the sealing problems previously presented.